Keith Rosenfield

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Recent posts by Keith Rosenfield

If you know everything about MDB that is in HF EJB that would be enough.
Hope that helps.
I passed the SCBCD with a score of 95% without a bit of work experience. I studied on average 4 hours a day for 2 months+. My main sources were HF EJB, the specification and this forum. I suppose my study time would have been reduced if I did have experience but experience does not guarantee success. Since the SCBCD covers EJB in its entirety it takes more than just experience. On the flip side, passing the SCBCD doesn't mean that you will be a profiecient EJB developer. I think that Sun should create a new certification for J2EE development. Passing this test would demonstrate to prospective employers that you not only know the syntax and semantics of EJB but how do make something useful with it.
Scalability - The ability to expand the number of users or increase the capabilities of a computing solution users without making major changes to the systems or application software.
Hi Vish,

Originally posted by Vish Kumar:
1. Also by default, all entity beans reentrant property have their
value set to false in the DD


Are you certain of this? My thinking is that since reentrant is a required tag that there is no default value.
Just my 2 cents.
I don't recall if there was a question on reentrant on my exam. To be on the safe side I recommend that you know that the only bean type that can be marked as reentrant are entity beans and that you indicate the whether an entity bean is reentrant through the required reentrant subtag of the entity tag in the deployment descriptor.
Edward,
You should not take the real exam until you can consistently get over 90% on the SoftSCBCD mock exams. If you do, you'll find the real test to be slightly easier than the mock tests and should expect a vert good score.
Good luck!!
Hey Edward

Originally posted by Edward Chen:
Q27. A stateful session bean ProcessOrder with container-managed transaction demarcation accesses another session bean ConfirmOrder. In which of the following methods ProcessOrder bean can access ConfirmOrder bean (select two):
A.setSessionContext
B.business methods from component interface
C.methods from javax.ejb.SessionBean interface
D.methods from javax.ejb.SessionSynchronization interface
softSCBCD give the answer: B. C . But I think only B is correct. Am I right?


I think you may be right. setSessionContext method is from javax.ejb.SessionBean and bean access is not allowed from this method.

Originally posted by Edward Chen:

---------
Entity beans
in the Home , create has to name transaction, therefore, ejbCreate()/ ejbPostcreate() in the Bean class has SAME transaction. This is correct?


That is correct. Page 172 of the spec says
An ejbPostCreate<METHOD>(...) method executes in the same transaction context as the previous ejbCreate<METHOD>(...) method.

Originally posted by Edward Chen:

if correct, then how about remove, we have different remove() in the Object and Home, so ejbRemove() should follow which transaction?


ejbRemove() runs in the same transaction context as the remove() method that initiated it.
Page 173 of the spec says:
This method and the database delete operation(s) execute in the transaction context determined by the transaction attribute of the remove method that triggered the ejbRemove method.
Hope this helps
Session bean state is not transactional. It is up to the bean developer to ensure that if a transaction fails that the state is reset.
There is not a question on the exam that you won't be able to answer if you read HF carefully for complete understanding. You should also refer to the spec when necessary. You should spend at least a week or two taking mock tests which will help bring out your week points. I would also reccomend Valentine Crettaz's cheat sheets, especially the life cycle diagrams. You can find them by following the SCBCD links link at the top of the page.
Good luck.
[ February 13, 2004: Message edited by: Keith Rosenfield ]
21 years ago
My guess would be 40 entity beans, one for each table.
I don't know the answer but I can relate to your frustration. During my exam preparation there were a lot of concepts that I had to accept on face value. I find it much easier to retain information when I know why it is. Besides, I have a very curious nature that compels me to know what makes things tick. Some of the "what's" of EJB I learned, I never learned the "why's".
[ February 13, 2004: Message edited by: Keith Rosenfield ]
HF is Head First EJB. If you were to use only one source, this would be it. I would also refer to the specification for those tricky areas.
Good luck.
21 years ago
Congratulations Reghu.

Our preparations and scores were very similar. I studied two months also and used basically the same materials and scored 95%. I'm glad to have played a role in your success.
BTW...you should update your signature to include SCBCD.
Good luck on your future pursuits.

[ February 13, 2004: Message edited by: Keith Rosenfield ]
21 years ago
Hey Pradeep,
To answer this question you should understand IN expressions. An IN expression allows you to determine if a particular string is a member of a set of strings. The IN expression evaluates to true if the string preceding the IN operator is a member of the set of strings following the IN operator or evaluates to false otherwise.
For example:
o.country IN (�UK�, �US�, �France�)
In this case o.country is a single_valued_path_expression. What is a single_valued_path_expression? This is just an expression that evaluated to a single value rather than a collection. In the case of IN expressions it only makes sense that the single_valued_path_expression evaluates to a string value, because you are testing for membership amoung a set of strings. The string that o.country represents is tested for membership in the set of strings that follow the IN.
The following from the spec make help clarify things:

11.2.7.8 In expressions
The syntax for the use of the comparison operator [NOT] IN in a conditional expression is as follows:
single_valued_path_expression [NOT] IN (string-literal [, string-literal]* )
The single_valued_path_expression must have a String value.



Hope this helps.
[ February 13, 2004: Message edited by: Keith Rosenfield ]
[ February 13, 2004: Message edited by: Keith Rosenfield ]
It appears that page 225 is missing the ejbCreate() part of the object creation. I imagine that the ejbObject is created at some point during or before this method. There will be only one ejbObject for a stateless session bean per home. A bean instance is pulled from the pool and tied to the ejbObject to service a business method. The bean is put back into the pool upon the completion of the business method.
If you think about it, the only thing that makes sense is for the ejbObject to be created upon bean creation. How else would clients be able to get a reference to the bean in order to call methods on it.
Hope this helps.
[ February 13, 2004: Message edited by: Keith Rosenfield ]